It is estimated that until now (November 2013) approximately 250,000 people worldwide have received cochlear implants. Cochlear implants are the most common form of implantable auditory prostheses. Cochlear implants enable people with moderate to severe sensorineural hearing disability to perceive sound, and provide sufficient auditory information in order to enable fairly sufficient listening comprehension in a quiet environment. During implantation, an electrode array is introduced into the cochlea which stimulates the auditory nerve by means of electrical impulses. In the case of the auditory nerve being damaged, a brain stem implant whose functionality is very similar to that of a cochlear implant is a better choice than an implantable auditory prosthesis. Regarding speech perception, however, brain stem implants usually are not able to achieve the efficiency of cochlear implants.
In contrast to electrode arrays that are used in implantable auditory prostheses, where each electrode corresponds to a specific frequency band, an intact cochlea comprises more than 3,000 inner hair cells, which enables much better frequency resolution (compared to the approximately 10-50 electrodes or frequency bands of common cochlear implants).
Apart from the users of implantable auditory prostheses (implanted auditory prostheses), approximately 40 million people with low-level to severe hearing loss use non-implanted hearing aids. While hearing aids in specific cases (mainly in conjunction with low-scale hearing loss) are able to restore the hearing capability at a high level, in most cases hearing supported by hearing aids still lags behind normal hearing.
Currently, speech processors for hearing aids, cochlear implants and brain stem implants use a multitude of pre-processing algorithms including automatic gain and sensitivity control, optimization of the dynamic range, background noise reduction, wind noise reduction, etc. Today, treatment by means of hearing aids and implantable auditory prostheses focuses on improving the perception of words and sentences. However, picking up (accompanying) information such as intonation is reduced for hearing aid users and often is not perceivable for implant users. As a consequence, these users are not able to perceive important elements of background information coded into prosody, or emotions linguistically expressed by the speaker. Often, implant users are not even able to determine if a sentence is a question or a statement, which may lead to uncertainties and social isolation.
It is the object of the present invention to improve the perception of linguistic background information such as prosody and/or emotions for hearing aid users and, in doing so, to improve participation in conversations with other people.